While the invention is subject to a wide range of applications, it is particularly suited for cutting sheets of very accurate length from long strips of metal or other material.
In cutting very thin sheets of continuous web which may include metal or paper, it is often necessary to very accruately repeat the same length of sheet during each cut. For instance, in the formation of honeycomb, a continuous web may be printed with glue lines as described in our co-pending U.S. patent application Ser. No. 56,462 filed on July 11, 1979. When the sheets are stacked on top of one another and joined together by heat and pressure, it is extremely important that the glue lines are properly lined up in order that the honeycomb is finished with cells of the same shape and in the proper location. Thus, the very thin material used in the construction of the honeycomb material, such as for example aluminum having a thickness of 0.0015 to 0.004 inches must be cut to a set length which is accurately established and maintained during the cutting process.
In the past, it has been known to cut sheets of material to an accurate length. For example, U.S. Pat. No. 2,637,394 to Fey, discloses for example, "A method for close tolerance cutting of sheets which the portion of a strip from which the sheet is being cut is bowed across its width and thereby made rigid so that the portion of the strip extending between two predetermined points will be a fixed length." This reference relies on the bowing of the strip across its width in order to stiffen the material to provide accurate cutting.
In the operation of a shear cutter, it is important that the web be fed at an appropriate time as well as the cutting device being operative when required. In U.S. Pat. No. 2,890,750 to Depken, there is disclosed for example, "The entrance of a continuous or elongated metal strip into a shearing machine changes the magnetic state of an electromagnetic sensing device to establish an electrical control signal. After a suitable time dealy to insure correct positioning of the incoming strip, the electrical control signal energizes suitable devices to start the successive shearing of the elongated strip into separate individual strips for lamentations." This reference is significantly different from the present invention because it is not concerned with the accurate cutting of very thin strips of web material.
It is an object of the present invention to provide an improved cutting apparatus for close tolerance cutting of sheets from a strip of web material.
It is a further object of the present invention to provide a cutting apparatus which holds the web in a rigid flat plane in order to accurately cut the web material.
It is a still further object of the present invention to provide a cutting apparatus which automatically feeds the strip of web material and cuts it into sheets of very accurate length.
It is a still further ojbect of the present invention to provide a cutting apparatus which senses the webs and disengages the feeding mechanism and activates a web shear.